WO2024099223A1 - 硼中子捕获治疗系统及照射剂量修正方法 - Google Patents

硼中子捕获治疗系统及照射剂量修正方法 Download PDF

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WO2024099223A1
WO2024099223A1 PCT/CN2023/129479 CN2023129479W WO2024099223A1 WO 2024099223 A1 WO2024099223 A1 WO 2024099223A1 CN 2023129479 W CN2023129479 W CN 2023129479W WO 2024099223 A1 WO2024099223 A1 WO 2024099223A1
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preset
dose
irradiation
neutron
boron concentration
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PCT/CN2023/129479
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English (en)
French (fr)
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邱鸿霖
邓逸樵
舒迪昀
刘渊豪
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中硼(厦门)医疗器械有限公司
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/02—Dosimeters
    • G—PHYSICS
    • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H20/00—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
    • G16H20/40—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture

Definitions

  • the present invention relates to a radiotherapy system, in particular to a boron neutron capture therapy system; the present invention relates to an irradiation dose correction method, in particular to a irradiation dose correction method for a boron neutron capture therapy system.
  • radiotherapy has become one of the main means of cancer treatment.
  • traditional photon or electron therapy is limited by the physical conditions of radiation itself. While killing tumor cells, it will also cause damage to a large number of normal tissues along the beam path.
  • traditional radiotherapy is often not effective for the treatment of malignant tumors that are more resistant to radiation (such as glioblastoma multiforme and melanoma).
  • boron neutron capture therapy in neutron capture therapy provides a better cancer treatment option than traditional radiotherapy by specifically aggregating boron-containing drugs in tumor cells and coordinating precise neutron beam control.
  • BNCT Boron Neutron Capture Therapy
  • 10B Boron Neutron Capture Therapy
  • 10B boron
  • 10B neutron
  • n, ⁇ 7Li neutron capture and nuclear fission reaction
  • two heavily charged particles 4He and 7Li
  • the average energy of the two heavily charged particles is about 2.33MeV, with high linear energy transfer (LET) and short range characteristics.
  • the linear energy transfer and range of ⁇ particles are 150keV/ ⁇ m and 8 ⁇ m, respectively, while those of 7Li heavy charged particles are 175keV/ ⁇ m and 5 ⁇ m.
  • the total range of the two particles is approximately equivalent to the size of a cell. Therefore, the radiation damage caused to the organism can be limited to the cellular level.
  • boron-containing drugs selectively accumulate in tumor cells and are combined with appropriate neutron sources, the purpose of locally killing tumor cells can be achieved without causing too much damage to normal tissues.
  • the neutron beam that irradiates the irradiated body The radiation is strong, and the radiation dose to the irradiated body needs to be precisely controlled to achieve a good treatment effect while minimizing the radiation damage caused to the irradiated body. Therefore, the accuracy of the treatment plan is crucial.
  • the treatment plan is formulated using a preset blood boron concentration for simulation calculation to estimate the irradiation.
  • the irradiated body is continuously injected with boron-containing drugs, and the blood of the irradiated body is drawn before the irradiated body enters the irradiation room for irradiation treatment to measure the actual blood boron concentration of the irradiated body.
  • the boron-containing drug is continuously injected into the blood to maintain the blood boron concentration.
  • the accuracy of the neutron beam irradiation dose is crucial in practical treatment. Too much irradiation dose will cause potential damage to the irradiated body, and too little irradiation dose will reduce the quality of treatment.
  • the neutron beam irradiation dose is determined by the blood boron concentration and the neutron dose of the neutron beam actually irradiated to the irradiated body. In the actual treatment process, a preset treatment plan is usually obtained by simulation calculation based on the preset boron concentration.
  • the preset treatment plan formulated according to the preset blood boron concentration has errors. It is necessary to provide a boron neutron capture therapy system and irradiation dose correction method that can correct the preset treatment plan to ensure the treatment effect.
  • the present invention provides a neutron capture therapy system, which includes: a neutron beam irradiation module, which is used to generate a neutron beam; a blood boron concentration detection device, which is used to detect the actual blood boron concentration of the irradiated body; a treatment plan module, which is used to generate a preset treatment plan; an irradiation dose correction module, which obtains a corrected irradiation dose according to the actual blood boron concentration; and a control module, which is used to call the preset treatment plan from the treatment plan module and control the irradiation time of the neutron beam irradiation module according to the corrected irradiation dose, so that the irradiation dose received by the patient reaches the target dose.
  • a neutron beam irradiation module which is used to generate a neutron beam
  • a blood boron concentration detection device which is used to detect the actual blood boron concentration of the irradiated body
  • a treatment plan module which is used
  • the treatment plan module obtains the preset treatment plan by simulation calculation based on the preset blood boron concentration.
  • the irradiation dose correction module corrects the target dose rate according to the actual blood boron concentration to obtain the corrected irradiation dose.
  • the boron neutron capture therapy system also includes a neutron dose detection device for real-time detection of cumulative neutron counts to obtain irradiation doses.
  • the neutron dose detection device is a BF 3 proportional counter.
  • N preset RBF3 , cal ⁇ T preset (1)
  • R BF3,cal is the theoretical count rate of the neutron dose detection device
  • B preset is the preset boron concentration
  • T preset is the preset irradiation time corresponding to the preset boron concentration B preset
  • T preset is calculated using the following formula 2:
  • D ROI prescribed is the target dose
  • Formula 3 is used for calculation, and formula 3 is as follows:
  • a, b, and c are fitting coefficients, which are obtained by function fitting of multiple preset boron concentration values and their corresponding simulated dose rates.
  • T update is the planned irradiation time corresponding to the actual blood boron concentration
  • B update is the corrected target dose rate corresponding to the actual blood boron concentration B update
  • the calculation is performed using the following formula 5:
  • a, b, and c are fitting coefficients, which are obtained by function fitting of multiple preset boron concentration values and their corresponding simulated dose rates.
  • Another aspect of the present invention provides a method for correcting the irradiation dose of a boron neutron capture therapy system, which comprises: generating a preset treatment plan by combining a preset boron concentration and medical imaging data of an irradiated body; obtaining a corrected irradiation dose according to the actual boron concentration; and controlling the irradiation time according to the corrected irradiation dose so that the patient The radiation dose received reached the target dose.
  • the irradiation dose correction method also includes a step of determining a target dose based on medical imaging data of the irradiated body.
  • the irradiation dose correction method also includes the step of obtaining a preset irradiation dose.
  • the corrected irradiation dose is obtained by correcting a preset target dose rate in the preset treatment plan according to the actually detected boron concentration value to obtain a corrected target dose rate, and calculating the corrected irradiation dose according to the corrected target dose rate.
  • N preset RBF3 , cal ⁇ T preset (1)
  • R BF3,cal is the theoretical count rate of the neutron dose detection device
  • B preset is the preset boron concentration
  • T preset is the preset irradiation time corresponding to the preset boron concentration B preset
  • T preset is calculated using the following formula 2:
  • a, b, and c are fitting coefficients, which are obtained by function fitting of multiple preset boron concentration values and their corresponding simulated dose rates.
  • T update is the planned irradiation time corresponding to the actual blood boron concentration
  • B update is the corrected target dose rate corresponding to the actual blood boron concentration B update
  • the calculation is performed using the following formula 5:
  • a, b, and c are fitting coefficients, which are obtained by function fitting of multiple preset boron concentration values and their corresponding simulated dose rates.
  • the irradiation dose correction method also includes a neutron agent for real-time detection of the irradiation dose.
  • the neutron dose detection device is configured to detect the irradiation dose, and when the irradiation dose detected by the neutron dose detection device reaches the corrected irradiation dose, the control module controls the neutron beam irradiation module to stop irradiation.
  • the neutron dose detection device obtains the irradiation dose by real-time detection of the cumulative neutron count, and is specifically a BF 3 proportional counter.
  • a preset treatment plan is generated according to a preset blood boron concentration, and the preset target dose rate in the preset treatment plan is corrected according to the actual blood boron concentration to obtain a corrected target dose rate.
  • the corrected neutron dose is calculated according to the corrected target dose rate to control the irradiation treatment time of the neutron irradiation module.
  • FIG1 is a block diagram of a boron neutron capture therapy system according to an embodiment of the present invention.
  • FIG2 is a schematic diagram of the layout of a boron neutron capture therapy system according to an embodiment of the present invention.
  • FIG3 is a schematic diagram of a beam shaping body according to an embodiment of the present invention.
  • FIG. 4 is a flow chart of an irradiation dose correction method according to an embodiment of the present invention.
  • boron neutron capture therapy system 100 neutron beam irradiation module 1, neutron generating device 11, accelerator 111, target 112, beam shaper 12, reflector 121, retarder 122, thermal neutron absorber 123, radiation shield 124, beam outlet 125, collimator 13, image acquisition module 2, neutron dose detection device 3, blood boron concentration detection device 4, treatment planning module 5, control module 6, loading module 7, irradiation dose correction module 8, irradiated object S.
  • the boron neutron capture therapy system 100 in this embodiment includes a neutron beam irradiation module 1, an image acquisition module 2, a neutron dose detection device 3, a blood boron concentration detection device 4, a treatment planning module 5, an irradiation dose correction module 8, a control module 6 and a loading module 7.
  • the neutron beam irradiation Module 1 is used to generate a neutron beam suitable for treatment, which includes a neutron generator 11, a beam shaper 12 and a collimator 13.
  • the neutron generator 11 is used to generate a neutron beam
  • the beam shaper 12 is used to adjust the beam quality of the neutron beam generated by the neutron generator 11 and reduce unnecessary dose deposition
  • the collimator 13 is used to converge the neutron beam so that the neutron beam has a higher targeting during treatment
  • the neutron dose detection device 3 is used to detect the neutron dose of the neutron beam generated by the neutron beam irradiation module 1
  • the blood boron concentration detection device 4 is used to detect the actual blood boron concentration of the irradiated body S
  • the treatment plan module 5 is used to generate a preset treatment plan
  • the irradiation dose correction module obtains a corrected irradiation dose according to the actual blood boron concentration detected by the blood boron concentration detection device 4
  • the control module 6 retrieves the preset treatment plan of the current irradiated body S from the treatment plan module 5, and controls the neutron beam irradiation module 1 to perform irradiation treatment according to the corrected
  • the main principle of BNCT is that after the irradiated body S takes or is injected with a boron ( B- 10) drug, the boron (B-10) drug selectively accumulates in tumor cells. Then, the boron ( B -10) drug has a high capture cross-section for thermal neutrons, and generates two heavily charged particles, 4 He and 7 Li, through 10 B(n, ⁇ ) 7 Li neutron capture and nuclear fission reactions.
  • the average energy of the two heavily charged particles is about 2.33 MeV, and they have high linear energy transfer (LET) and short range characteristics.
  • the total range of the two particles is approximately equivalent to the size of a cell. Therefore, the radiation damage caused to the organism can be limited to the cellular level, and the purpose of locally killing tumor cells can be achieved without causing too much damage to normal tissues.
  • the neutron generating device 11 includes an accelerator 111 and a target material 112.
  • the accelerator 111 is used to accelerate charged particles (such as protons, deuterons, etc.) to generate charged particle beams such as proton beams.
  • the charged particle beams irradiate the target material 112 and react with the target material 112 to generate neutron beams (neutron beams).
  • the target material 112 is preferably a metal target material 112.
  • the appropriate nuclear reaction is selected based on the required neutron yield and energy, the energy and current of the accelerated charged particles that can be provided, and the physical and chemical properties of the metal target material 112.
  • a target material 112 made of lithium metal is used.
  • the material of the target 112 can also be made of metal materials other than lithium and beryllium, such as tantalum (Ta) or tungsten (W);
  • the target 112 can be in the shape of a disk, or other solid shapes, or a liquid (liquid metal);
  • the accelerator can be a linear accelerator, a cyclotron, a synchrotron, or a synchrocyclotron.
  • the neutron generating device can be a nuclear reactor instead of a accelerator. accelerator and target.
  • the neutron source of the boron neutron capture therapy comes from a nuclear reactor or a nuclear reaction between accelerated charged particles and the target material 112
  • what is actually produced is a mixed radiation field, that is, the generated beam contains neutrons and photons ranging from low energy to high energy.
  • the generated beam contains neutrons and photons ranging from low energy to high energy.
  • the beam shaper 12 can adjust the beam quality of the neutron beam generated by the neutron generator 11 and reduce unnecessary dose deposition.
  • the collimator 13 is used to converge the neutron beam so that the neutron beam has a higher targeting during the treatment process.
  • the beam shaping body 12 includes a reflector 121, a retarder 122, a thermal neutron absorber 123, a radiation shield 124 and a beam outlet 125.
  • the retarder 122 can adjust the energy of fast neutrons (>40keV) from the neutron generator 11 to the epithermal neutron energy region (0.5eV-40keV) and reduce the content of thermal neutrons ( ⁇ 0.5eV) as much as possible; the retarder 122 is made of a material with a large cross section for fast neutrons and a small cross section for epithermal neutrons.
  • the retarder 122 is made of D 2 O, AlF 3 , Fluental TM , CaF 2 , Li 2 CO 3 , MgF 2 and Al 2 O 3 ; the reflector 121 surrounds the retarder 122, and reflects the neutrons that diffuse through the retarder 122 back to the neutron beam to improve the utilization rate of the neutrons. It is made of a material with strong neutron reflection ability.
  • the reflector 121 is made of at least one of Pb or Ni; on the transmission path of the neutron beam, the thermal neutron absorber 123 is arranged at the rear of the retarder 122, and is used to absorb the thermal neutrons that pass through the retarder 122 to reduce the content of thermal neutrons in the neutron beam. It is made of a material with a large cross-section for interacting with thermal neutrons. As a preferred embodiment, the thermal neutron absorber 123 is made of Li -6 .
  • the material of the retarder 122 contains Li -6
  • the thermal neutron absorber 123 may not be provided separately, but the retarder 122 may be used as the thermal neutron absorber 123; the radiation shielding body 124 is used to shield the neutrons and photons leaked from the part other than the beam outlet 125, and the material of the radiation shielding body 124 includes at least one of a photon shielding material and a neutron shielding material.
  • the material of the radiation shielding body 124 includes a photon shielding material lead (Pb) and a neutron shielding material polyethylene (PE).
  • the collimator 13 is arranged at the rear of the beam outlet 125.
  • the epithermal neutron beam coming out of the collimator 13 is irradiated to the irradiated body S. After passing through the shallow normal tissue of the irradiated body S, the epithermal neutron beam is slowed down to thermal neutrons to reach the tumor cells to achieve the purpose of treatment.
  • the beam shaping body 12 may have other structures as long as an epithermal neutron beam that meets the treatment requirements can be obtained; the present invention may not have the collimator 13, and the beam directly irradiates the irradiated body S after exiting the beam outlet 125 of the beam shaping body 12.
  • the outlet of the collimator 13 may also be interpreted as the beam outlet 125.
  • the device for acquiring three-dimensional medical images can be CT, MRI, PET, ultrasound and other imaging devices.
  • the present invention preferably adopts the CT device image acquisition module 2, and adopts electronic computed tomography (Computed Tomography, CT) to acquire the medical image data of the irradiated body S.
  • the medical image data of the irradiated body S includes the coordinate matrix and CT value matrix of the medical image voxel model of the part to be irradiated (lesion, i.e., tumor cell) in the medical image coordinate system.
  • the neutron dose detection device 3 includes a detector for receiving neutrons and outputting signals, a signal processing unit for processing the signal output from the detector, a counter for counting the signal output from the signal processing unit to obtain a count rate, a conversion unit for converting the count rate recorded by the counter into a neutron flux rate or a neutron dose rate, a calculation unit for integrating the neutron flux rate or the neutron dose rate to obtain a neutron dose, and a display for displaying the neutron dose.
  • the neutron dose detected by the neutron dose detection device 3 is the irradiation dose received by the irradiated body S.
  • the detector may be placed in the beam shaper 12, in the collimator 13, or at any position adjacent to the beam shaper 12, as long as the detector is located at a position that can be used to detect the neutron dose of the neutron beam.
  • Detectors that can detect the neutron dose of a neutron beam in real time include ionization chambers and scintillation detectors.
  • the He -3 proportional counter, BF 3 proportional counter, fission ionization chamber, and boron ionization chamber are based on the ionization chamber structure.
  • the scintillation detector contains organic materials or inorganic materials. When detecting thermal neutrons, the scintillation detector often adds high thermal neutron capture cross-section elements such as Li or B.
  • An element in the two types of detectors captures or undergoes nuclear fission reactions with neutrons entering the detector to release heavily charged particles and nuclear fission fragments, generating a large number of ionization pairs in the ionization chamber or scintillation detector. These charges are collected and form electrical signals, which are processed by the signal processing unit for noise reduction, conversion, and separation, and the electrical signals are converted into pulse signals.
  • the signal processing unit for noise reduction, conversion, and separation, and the electrical signals are converted into pulse signals.
  • neutron pulse signals and gamma pulse signals are distinguished.
  • the separated neutron pulse signals are continuously recorded by the counter to obtain the neutron counting rate (n/s).
  • the conversion unit calculates and converts the counting rate through internal software and programs to obtain the neutron flux rate (cm - 2s -1 ). Further calculation and conversion are performed to obtain the neutron dose rate (Gy/s).
  • the integration unit integrates the neutron dose rate to obtain the real-time neutron dose.
  • the neutron beam When the neutron beam passes through the fission ionization chamber, it interacts with the gas molecules inside the fission ionization chamber or the wall of the fission ionization chamber to generate electrons and positively charged ions, which are called the above-mentioned ion pairs. Due to the external electric field high voltage in the fission ionization chamber, the electrons move toward the central anode wire and the positively charged ions move toward the surrounding cathode walls, thus generating a measurable electrical signal.
  • the optical fiber and other materials in the scintillation detector absorb energy and generate visible light. It uses ionizing radiation to excite the electrons in the crystal or molecule to an excited state. When the electrons return to the ground state, the fluorescence emitted is collected and used as neutron beam detection. The visible light emitted by the scintillation detector after the neutron beam interacts is converted into an electrical signal output using a photomultiplier tube.
  • the BF 3 proportional counter is placed in the beam shaper to receive neutron beam irradiation.
  • the B element in the BF 3 proportional counter reacts with neutrons to form 10 B(n,alpha) 7 Li.
  • the alpha particles and 7 Li electric particles produced by the nuclear reaction are collected by high-voltage electrodes under the drive of voltage to generate electrical signals.
  • the electrical signal is transmitted to the signal processing unit through a coaxial cable for signal amplification and filtering and shaping to form a pulse signal.
  • the processed pulse signal is transmitted to the counter for pulse counting to obtain the counting rate (n/s).
  • the counting rate can be used to measure the neutron beam intensity, that is, the neutron dose, in real time.
  • a BF 3 proportional counter is preferably used to detect the neutron dose.
  • the type of detector is not limited thereto, as long as it can detect the neutron dose in real time.
  • the actual blood boron concentration in the irradiated body needs to be detected by a blood boron concentration detection device 4, and the preset irradiation dose is corrected according to the actual blood boron concentration.
  • the detection of boron concentration can be achieved by inductively coupled plasma spectroscopy, high-resolution ⁇ radioautography, charged ion spectroscopy, neutron capture camera, nuclear magnetic resonance and magnetic resonance imaging, positron emission tomography, prompt gamma-ray spectrometer, etc.
  • the device involved in the above detection method is called a boron concentration detection device.
  • the mounting module 7 includes a mounting table that supports the irradiated object S and a driving unit that drives the mounting table to move to an irradiation position.
  • the irradiation dose modification of the boron neutron capture therapy system 100 in one embodiment of the present invention is The correct method includes the following steps:
  • a preset treatment plan is generated in combination with the preset boron concentration and the medical imaging data of the irradiated body.
  • the preset treatment plan includes preset irradiation parameters such as a preset irradiation time T preset and a preset target dose rate.
  • the target dose D ROI, prescribed is the actual neutron dose that the irradiated body needs to receive.
  • some of the above parameters or more unmentioned parameters may be understood as preset irradiation parameters.
  • the cumulative neutron count is used as a monitoring parameter of the BNCT online monitoring system for the irradiation dose.
  • the irradiation dose is corrected by calculating and correcting the cumulative neutron count. When the cumulative neutron count reaches the target value, the irradiation dose reaches the target dose.
  • R BF3,cal is the theoretical counting rate of the neutron dose detection device 3
  • T preset is the preset irradiation time corresponding to the preset boron concentration B preset , which is calculated using the following formula 2:
  • Preset target dose rate Formula 3 is used for calculation, and formula 3 is as follows:
  • a, b, and c are fitting coefficients, which are obtained by function fitting of multiple preset boron concentration values and their corresponding simulated dose rates.
  • the irradiation dose is corrected according to the actual boron concentration to obtain a corrected irradiation dose.
  • the corrected cumulative neutron count N update is obtained as a parameter basis for determining whether the target dose has been reached.
  • the blood boron concentration of the irradiated body is detected by the blood boron concentration detection device 4.
  • the corrected cumulative neutron count N update corresponding to the actual blood boron concentration B update is calculated using Formula 4, which is as follows:
  • T update is the planned irradiation time corresponding to the actual blood boron concentration B update
  • corrected target dose rate is the corrected target dose rate corresponding to the actual blood boron concentration B update
  • a, b, and c are fitting coefficients, which are obtained by function fitting of multiple preset boron concentration values and their corresponding simulated dose rates.
  • the control module 6 controls the neutron beam irradiation module 1 to stop irradiation to end the treatment.
  • the control module 6 controls the neutron beam irradiation module 1 to stop irradiation to end the treatment.
  • the neutron dose detection device 3 detects the irradiation dose of the neutron beam in real time, and stops the irradiation when the neutron irradiation dose reaches the corrected irradiation dose or the preset target dose; in other embodiments, irradiation control can be achieved by monitoring the irradiation time. Specifically, the required target irradiation time is calculated based on the corrected irradiation dose or the preset target dose.
  • control module 6 controls the neutron beam irradiation module 1 to stop irradiation to end the treatment, that is, step S4 can be based on the target irradiation time.
  • the target irradiation time T is calculated using Formula 6, which is as follows:
  • R BF3,cal is the count rate of the BF3 proportional counter under given reference source conditions
  • R BF3,QC is the BF3 count rate measured in the daily beam QC, which reflects the BF3 neutron count rate level on the day of irradiation
  • T1 is the irradiation time corresponding to the blood boron concentration B1 , which is calculated using formulas 7 and 8.
  • Formulas 7 and 8 are as follows:
  • a blood boron concentration detection device 4 is used to detect the actual blood boron concentration of the irradiated body, and the corrected irradiation time is calculated according to the actual blood boron concentration of the irradiated body before the irradiation therapy is performed; in other embodiments, during the irradiation process, the actual irradiation parameters will change, and it is necessary to adjust the target irradiation parameters periodically or in real time according to the specific situation to maximize the treatment effect.
  • the target dose rate changes with the change of blood boron concentration
  • the prescription dose that is, the target dose
  • the irradiation dose and the target irradiation time need to be further corrected to ensure that the neutron dose actually received by the irradiated body is consistent with the prescription dose to ensure the treatment effect.
  • an embodiment of the present invention may further include step S5, detecting the blood boron concentration of the irradiated body in real time or periodically during the actual irradiation process, correcting the irradiation dose or target irradiation time in real time or periodically according to the detected blood boron concentration, and repeating steps S3-S4 until the neutron dose detected by the neutron dose detection device 3 reaches the target dose or the actual irradiation time is equal to the corrected target irradiation time; on the other hand, the parameters of the neutron beam generated by the neutron irradiation module may also change.
  • the neutron dose detection device 3 can monitor the beam parameters of the neutron beam in real time. When the beam parameters of the neutron beam change, the target irradiation time can also be appropriately corrected to ensure that the neutron dose actually received by the irradiated body is consistent with the prescribed dose.
  • One embodiment of the present invention is described by taking the method of estimating the boron concentration in the irradiated body S by detecting the gamma rays released by the irradiated body S as an example. After the neutron beam enters the body of the irradiated body and reacts with boron, gamma rays are generated. By measuring the amount of gamma rays, the amount of boron that reacts with the neutron beam can be estimated, thereby estimating the boron concentration in the body of the irradiated body S.
  • a boron concentration detection device detects the gamma rays (478kev) generated by the reaction of neutrons and boron to determine the boron concentration
  • a boron distribution measurement system is provided that can measure the distribution of boron concentration by measuring single-energy gamma rays.
  • PG Prompt- ⁇
  • SPECT is a boron concentration detection device, which has a ⁇ -ray detection unit and a boron concentration calculation unit.
  • the ⁇ -ray detection unit is used to detect information related to the ⁇ -rays emitted from the body of the irradiated body S.
  • the boron concentration calculation unit calculates the boron concentration in the body of the irradiated body S based on the information related to the ⁇ -rays detected by the ⁇ -ray detection unit.
  • the ⁇ -ray detection unit can use a scintillator and other various ⁇ -ray detection equipment.
  • the ⁇ -ray detection unit is arranged near the tumor of the irradiated body S, for example, at a position about 30 cm away from the tumor of the irradiated body S.
  • the boron neutron capture therapy system 100 of the present invention obtains a preset treatment plan based on a preset blood boron concentration simulation, thereby obtaining a preset target dose, and then calculates a corrected irradiation dose based on a dose rate corresponding to the actual blood boron concentration.
  • the neutron irradiation module is controlled accordingly to implement irradiation therapy.
  • There is no need to inject boron-containing drugs into the irradiated body when formulating a preset treatment plan and there is no need to wait for the blood boron concentration to be detected before implementing irradiation, which saves treatment costs and simplifies the treatment process.
  • the target irradiation dose is corrected according to the actual blood boron concentration, reducing the error of the irradiation dose caused by changes in blood boron concentration during actual irradiation.
  • steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

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Abstract

本申请涉及一种硼中子捕获治疗系统及照射剂量修正方法，所述硼中子捕获治疗系统包括用于产生中子束的中子束照射模块、用于检测被照射体的实际血硼浓度的血硼浓度检测装置、用于生成预设治疗计划的治疗计划模块、根据所述实际血硼浓度获得修正照射剂量的照射剂量修正模块及控制模块，控制模块用于从所述治疗计划模块调取所述预设治疗计划，并根据所述修正照射剂量控制所述中子束照射模块的照射时间，使患者接受的照射剂量达到目标剂量，降低了实际照射时因血硼浓度变化带来的照射剂量的误差。

Description

硼中子捕获治疗系统及照射剂量修正方法 技术领域
本发明涉一方面涉及一种放射治疗系统，尤其涉及一种硼中子捕获治疗系统；本发明另一方面涉及一种照射剂量修正方法，尤其涉及一种硼中子捕获治疗系统的照射剂量修正方法。
背景技术
随着原子科学的发展，例如钴六十、直线加速器、电子射束等，放射线治疗已成为癌症治疗的主要手段之一。然而传统光子或电子治疗受到放射线本身物理条件的限制，在杀死肿瘤细胞的同时，也会对射束途径上大量的正常组织造成伤害；另外由于肿瘤细胞对放射线敏感程度的不同，传统放射治疗对于较具抗辐射性的恶性肿瘤(如：多行性胶质母细胞瘤(glioblastoma multiforme)、黑色素细胞瘤(melanoma))的治疗成效往往不佳。
为了减少对肿瘤周边正常组织的辐射伤害，化学治疗(chemotherapy)中的标靶治疗概念便被应用于放射线治疗中；而针对高抗辐射性的肿瘤细胞，目前也积极发展具有高相对生物效应(relative biological effectiveness,RBE)的辐射源治疗方法，如质子治疗、重粒子治疗、中子捕获治疗等。其中，中子捕获治疗中的硼中子捕获治疗借由含硼药物在肿瘤细胞的特异性集聚，配合精准的中子射束调控，提供了一种比传统放射线治疗更好的癌症治疗选择。
硼中子捕获治疗(Boron Neutron Capture Therapy,BNCT)是利用含硼(10B)药物对热中子具有高捕获截面的特性，借由10B(n,α)7Li中子捕获及核分裂反应产生4He和7Li两个重荷电粒子，两重荷电粒子的平均能量约为2.33MeV，具有高线性转移(Linear Energy Transfer,LET)、短射程特征，α粒子的线性能量转移与射程分别为150keV/μm、8μm，而7Li重荷粒子则为175keV/μm、5μm，两粒子的总射程约相当于一个细胞大小，因此对于生物体造成的辐射伤害能局限在细胞层级，当含硼药物选择性地聚集在肿瘤细胞中，搭配适当的中子射源，便能在不对正常组织造成太大伤害的前提下，达到局部杀死肿瘤细胞的目的。
在硼中子捕获治疗过程中，由于对被照射体进行辐射线照射治疗的中子束 辐射线较强，需要精确控制对被照射体实施的照射剂量以在达到较好的治疗效果的同时尽量降低辐射线对被照射体造成的辐射损伤，因此，治疗计划的制定的准确度至关重要。在临床实践中，由于目前BPA等可以作为硼中子捕获治疗用的含硼药物价格普遍较高，为节约被照射体的治疗费用并简化治疗流程，治疗计划制定采用预设的血硼浓度进行模拟计算以估算照射。在实际治疗过程中，向被照射体持续注射含硼药物，在被照射体进入照射室进行照射治疗之前抽取被照射体的血液测量被照射体的实际血硼浓度，在照射过程中持续注入含硼药物维持血液中的血硼浓度。
中子束的照射剂量的精准度在实践治疗中至关重要，照射剂量过多将对被照射体造成潜在的伤害，照射剂量过少则降低治疗质量，而中子束的照射剂量由血硼浓度和实际照射至被照射体的中子束的中子剂量决定。在实际治疗流程中，通常根据预设的硼浓度进行模拟计算得到预设治疗计划，由于不同的被照射体代谢情况不同，另外，不同药物和不同注射方式会导致被照射体血液硼浓度值范围出现差异，从而导致预设的血硼浓度与被照射体的实际血硼浓度存在差异，因此根据预设的血硼浓度制定的预设治疗计划存在误差。需要提供一种能够对预设治疗计划进行修正以保证治疗效果的硼中子捕获治疗系统及照射剂量修正方法。
发明内容
基于此，有必要针对上述技术问题，提供一种能够保证治疗效果的硼中子捕获治疗系统及照射剂量修正方法。
本发明一方面提供一种中子捕获治疗系统，其包括：中子束照射模块，用于产生中子束；血硼浓度检测装置，用于检测被照射体的实际血硼浓度；治疗计划模块，用于生成预设治疗计划；照射剂量修正模块，根据所述实际血硼浓度获取修正照射剂量；及控制模块，用于从所述治疗计划模块调取所述预设治疗计划，并根据所述修正照射剂量控制所述中子束照射模块的照射时间，使患者接受的照射剂量达到目标剂量。
进一步的，所述治疗计划模块根据预设血硼浓度模拟计算得到所述预设治疗计划。
进一步的，所述照射剂量修正模块根据所述实际血硼浓度修正目标剂量率得到所述修正照射剂量。
进一步的，所述硼中子捕获治疗系统还包括用于实时检测累积中子计数而获得照射剂量的中子剂量检测装置。
进一步的，所述中子剂量检测装置为BF3比例计数器。
进一步的，预设累积中子计数Npreset采用公式1进行计算，公式1如下：
Npreset＝RBF3，cal×Tpreset     (1)
其中，RBF3,cal为中子剂量检测装置的理论计数率、Bpreset为预设硼浓度、Tpreset为预设硼浓度Bpreset对应的预设照射时间，Tpreset采用如下公式2进行计算：
其中，DROI，prescribed为目标剂量、为预设目标剂量率，采用公式3进行计算，公式3如下：
其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应的模拟得到的剂量率通过函数拟合得到。
进一步的，修正累积中子计数Nupdate采用如下公式4计算：
其中，Bupdate为实际血硼浓度、Tupdate为实际血硼浓度Bupdate对应的计划照射时间、为实际血硼浓度Bupdate对应的修正目标剂量率，采用如下公式5进行计算：
其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应的模拟得到的剂量率通过函数拟合得到。
本发明另一方面还提供一种硼中子捕获治疗系统的照射剂量修正方法，其包括：结合预设硼浓度及被照射体的医学影像数据生成预设治疗计划；根据实际硼浓度获得修正照射剂量；及根据所述修正照射剂量控制照射时间，使患者 接受的照射剂量达到目标剂量。
进一步的，所述照射剂量修正方法还包括基于被照射体的医学影像数据确定目标剂量的步骤。
进一步的，所述照射剂量修正方法还包括获取预设照射剂量的步骤。
进一步的，获得所述修正照射剂量具体为：根据实际检测到的硼浓度值修正所述预设治疗计划中的预设目标剂量率得到修正目标剂量率，根据修正目标剂量率计算得到所述修正照射剂量。
进一步的，预设累积中子计数Npreset采用公式1进行计算，公式1如下：
Npreset＝RBF3，cal×Tpreset     (1)
其中，RBF3,cal为中子剂量检测装置的理论计数率、Bpreset为预设硼浓度、Tpreset为预设硼浓度Bpreset对应的预设照射时间，Tpreset采用如下公式2进行计算：
DROI，prescribed为目标剂量、为预设目标剂量率，采用公式3进行计算，公式3如下：
其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应模拟得到的剂量率通过函数拟合得到。
进一步的，所述修正累积中子计数Nupdate采用如下公式4计算：
其中，Bupdate为实际血硼浓度、Tupdate为实际血硼浓度Bupdate对应的计划照射时间、为实际血硼浓度Bupdate对应的修正目标剂量率，采用如下公式5进行计算：
其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应的模拟得到的剂量率通过函数拟合得到。
进一步的，所述照射剂量修正方法还包括用于实时检测照射剂量的中子剂 量检测装置，当中子剂量检测装置检测到的照射剂量到达所述修正照射剂量时，控制模块控制中子束照射模块停止照射。
进一步地，所述中子剂量检测装置通过实时检测累积中子计数而获得照射剂量，具体为BF3比例计数器。
本发明一实施例的硼中子捕获治疗系统的照射剂量修正方法中，根据预设血硼浓度生成预设治疗计划，并根据实际血硼浓度修正预设治疗计划中的预设目标剂量率得到修正目标剂量率，根据修正目标剂量率计算得到修正中子剂量，控制中子照射模块的照射治疗时间，无需在制定预设治疗计划时向被照射体注射含硼药物，且无需等血硼浓度检测出结果后再实施照射，节约了治疗成本、简化了治疗流程，在治疗过程中根据实际血硼浓度修正照射剂量，降低了实际照射时因血硼浓度变化带来的实际照射剂量与目标剂量的误差。
附图说明
图1为本发明一实施例硼中子捕获治疗系统的框图；
图2为本发明一实施例硼中子捕获治疗系统的布局示意图；
图3为本发明一实施例射束整形体的示意图；
图4为本发明一实施例照射剂量修正方法的流程图。
附图标记：硼中子捕获治疗系统100、中子束照射模块1、中子产生装置11、加速器111、靶材112、射束整形体12、反射体121、缓速体122、热中子吸收体123、辐射屏蔽体124、射束出口125、准直器13、影像获取模块2、中子剂量检测装置3、血硼浓度检测装置4、治疗计划模块5、控制模块6、载置模块7、照射剂量修正模块8、被照射体S。
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行详细说明。应当理解，此处描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
参照图1所示，本实施例中的硼中子捕获治疗系统100包括中子束照射模块1、影像获取模块2、中子剂量检测装置3、血硼浓度检测装置4、治疗计划模块5、照射剂量修正模块8、控制模块6及载置模块7。具体的，中子束照射 模块1用于产生适合治疗用的中子束，其包括中子产生装置11、射束整形体12及准直器13，中子产生装置11用于产生中子束，射束整形体12用于调整中子产生装置11产生的中子束的射束品质，降低不必要的剂量沉积，准直器13用以汇聚中子束，使中子束在进行治疗的过程中具有较高的靶向性；中子剂量检测装置3用于检测中子束照射模块1产生的中子束的中子剂量；血硼浓度检测装置4用于检测被照射体S的实际血硼浓度；治疗计划模块5用于生成预设治疗计划；照射剂量修正模块根据血硼浓度检测装置4检测到的实际血硼浓度获得修正照射剂量；控制模块6从治疗计划模块5调取当前被照射体S的预设治疗计划，并根据修正照射剂量控制中子束照射模块1执行照射治疗；载置模块7用于载置被照射体S。
硼中子捕获治疗的主要原理为：被照射体S服用或注射含硼(B-10)药物后，含硼药物选择性地聚集在肿瘤细胞中，然后利用含硼(B-10)药物对热中子具有高捕获截面的特性，借由10B(n,α)7Li中子捕获及核分裂反应产生4He和7Li两个重荷电粒子，两重荷电粒子的平均能量约为2.33MeV，具有高线性转移(Linear Energy Transfer,LET)、短射程特征，两粒子的总射程约相当于一个细胞大小，因此对于生物体造成的辐射伤害能局限在细胞层级，能够在不对正常组织造成太大伤害的前提下达到局部杀死肿瘤细胞的目的。
参照图2所示，本申请揭示的实施例中，中子产生装置11包括加速器111和靶材112，加速器111用于对带电粒子(如质子、氘核等)进行加速，产生如质子线的带电粒子束，带电粒子束照射到靶材112并与靶材112作用产生中子线(中子束)，靶材112优选为金属靶材112。依据所需的中子产率与能量、可提供的加速带电粒子能量与电流大小、金属靶材112的物化性等特性来挑选合适的核反应，常被讨论的核反应有7Li(p,n)7Be及9Be(p,n)9B，这两种反应皆为吸热反应。本发明的实施例中采用锂金属制成的靶材112。但是本领域技术人员熟知的，靶材112的材料也可以由锂、铍之外的金属材料制成，例如由钽(Ta)或钨(W)等形成；靶材112可以为圆板状，也可以为其他固体形状，也可以使用液状物(液体金属)；加速器可以是直线加速器、回旋加速器、同步加速器、同步回旋加速器。在其他实施方式在，中子产生装置可以是核反应堆而不采用加 速器和靶材。
无论硼中子捕获治疗的中子源来自核反应堆或加速带电粒子与靶材112的核反应，产生的实际上皆为混合辐射场，即产生的射束包含了低能至高能的中子、光子。对于深部肿瘤的硼中子捕获治疗，除了超热中子外，其余的辐射线含量越多，造成正常组织非选择性剂量沉积的比例越大，因此这些会造成不必要剂量沉积的辐射线含量应尽量降低。射束整形体12能够调整中子产生装置11产生的中子束的射束品质，降低不必要的剂量沉积，准直器13用以汇聚中子束，使中子束在进行治疗的过程中具有较高的靶向性。
结合图3所示，射束整形体12包括反射体121、缓速体122、热中子吸收体123、辐射屏蔽体124和射束出口125。缓速体122能够将从中子产生装置11出来的快中子能量(＞40keV)调整到超热中子能区(0.5eV-40keV)并尽可能减少热中子(＜0.5eV)含量；缓速体122由与快中子作用截面大、与超热中子作用截面小的材料制成，作为一种优选实施例，缓速体122由D2O、AlF3、FluentalTM、CaF2、Li2CO3、MgF2和Al2O3中的至少一种制成；反射体121包围缓速体122，并将穿过缓速体122向四周扩散的中子反射回中子射束以提高中子的利用率，其由中子反射能力强的材料制成，作为一种优选实施例，反射体121由Pb或Ni中的至少一种制成；在中子束的传输路径上，热中子吸收体123设置于缓速体122后部，用于吸收穿过缓速体122的热中子以减少中子束中热中子的含量，其由与热中子作用截面大的材料制成，作为一种优选实施例，热中子吸收体123由Li-6制成，在其他实施例中，由于缓速体122的材料中含有Li-6，热中子吸收体123可以不单独设置，而是以缓速体122作为热中子吸收体123；辐射屏蔽体124用于屏蔽从射束出口125以外部分渗漏的中子和光子，辐射屏蔽体124的材料包括光子屏蔽材料和中子屏蔽材料中的至少一种，作为一种优选实施例，辐射屏蔽体124的材料包括光子屏蔽材料铅(Pb)和中子屏蔽材料聚乙烯(PE)。
准直器13设置在射束出口125后部，从准直器13出来的超热中子束照向被照射体S，超热中子束经被照射体S的浅层正常组织后被缓速为热中子到达肿瘤细胞实现治疗目的。
可以理解，射束整形体12还可以有其他的构造，只要能够获得满足治疗要求的超热中子束即可；本发明也可以不具有准直器13，射束从射束整形体12的射束出口125出来后直接照射向被照射体S。为描述方便，当设置有准直器13时，准直器13的出口也可以解释为射束出口125。
获取三维医学影像的设备可以是CT、MRI、PET、超声等影像设备，本发明优选的采用CT设备影像获取模块2，采用电子计算机断层扫描(Computed Tomography,CT)获取被照射体S的医学影像数据。被照射体S的医学影像数据包括待照射部位(病灶，即肿瘤细胞)的医学影像体素模型在医学影像坐标系下的坐标矩阵及CT值矩阵。
中子剂量检测装置3包括用于接收中子并输出信号的检测器、用于处理从检测器输出的信号的信号处理单元、对从信号处理单元输出的信号进行计数得到计数率的计数器、将计数器记录的计数率转换为中子通量率或中子剂量率的转换单元、对中子通量率或中子剂量率进行积分计算得到中子剂量的计算单元及显示中子剂量的显示器。在本方案中，中子剂量检测装置3检测的中子剂量即被照射体S接受的照射剂量。
检测器可以放置在射束整形体12内、也可以放置在准直器13内、也可以设置在临近射束整形体12的任意位置，只要检测器所处的位置能够用来检测中子束的中子剂量即可。
能够实现实时检测中子束的中子剂量的检测器有电离室及闪烁探测头，其中采用电离室结构为基底的有He-3比例计数器、BF3比例计数器、分裂游离室、硼电离室，闪烁探测头包含有机材料或无机材料，在探测热中子时，闪烁探测头多添加Li或B等高热中子捕获截面元素。两类检测器内的某一元素与进入该检测器的中子发生捕获或核裂变反应释出重荷电粒子及核裂变碎片，于电离室或闪烁探测头内产生大量电离对，这些电荷被收集并形成电信号，经过信号处理单元进行降噪、转换、分离处理，并将电信号转为脉冲信号，并透过分析电压脉冲的大小，分辨出中子脉冲信号及γ脉冲信号。分离出来的中子脉冲信号被计数器持续记录下来，得到中子的计数率(n/s)。转换单元通过内部的软件、程序等对计数率进行运算和转换得到中子通量率(cm-2s-1),通过对中子通量率 进行进一步的运算和转换得到中子剂量率(Gy/s)，最后，积分部对中子剂量率进行积分获得实时中子剂量。
以下以分裂游离室(fission chamber)、闪烁探测头(scintillator detector)和BF3比例计数器为例做简单的介绍。
当中子束通过分裂游离室时，与分裂游离室内部气体分子或分裂游离室的壁部发生游离作用，生成电子与带正电荷的离子，此电子和正电荷离子称为上述的离子对。由于分裂游离室内有外加电场高压，因此电子朝中央阳极丝移动，正电荷离子朝周围的阴极壁移动，因而产生可测得的电信号。
闪烁探测头内的光纤等物质吸收能量之后会产生可见光，其利用游离辐射将晶体或分子中的电子激发至激态，而当电子回到基态时放出的荧光被收集后用来作为中子束检测。闪烁探测头与中子束作用后所发射的可见光，利用光电倍增管将可见光转化为电信号输出。
BF3比例计数器放置在射束整形体中用于接受中子束的照射，BF3比例计数器中的B元素与中子发生核反应10B(n,alpha)7Li，核反应产生的alpha粒子和7Li电粒子在电压的驱动下被高压电极收集，产生电信号。电信号通过同轴电缆传输到信号处理单元进行信号放大和滤波整形后形成脉冲信号。被处理后的脉冲信号传输到计数器中进行脉冲计数，获得计数率(n/s)，通过计数率可实时测定中子束强度，即中子剂量。
本发明的一实施例中，优选的采用BF3比例计数器实现中子剂量的检测，当然，检测器的种类不限于此，只要能够实时检测中子剂量即可。
在对被照射体S进行中子束照射治疗前，需采用血硼浓度检测装置4检测被照射体体内的实际血硼浓度，根据实际血硼浓度进行预设照射剂量的修正。硼浓度的检测可由电感耦合等离子体光谱法、高分辨率α放射自显影、带电离子能谱法、中子俘获相机、核磁共振和磁共振成像、正电子发射断层成像、瞬发γ射线能谱仪等实现，以上检测方法涉及的装置称为硼浓度检测装置。
载置模块7包括支撑被照射体S的载置台和驱动载置台移动到照射位置的驱动部。
参照图4所示，本发明一实施例中的硼中子捕获治疗系统100照射剂量修 正的方法包括以下步骤：
S1：生成预设治疗计划；
结合预设硼浓度及被照射体的医学影像数据生成预设治疗计划，预设治疗计划包括预设照射时间Tpreset、预设目标剂量率等预设照射参数。
医护人员结合被照射体的身体特征参数、被照射体的医学影像数据及自身经验设定目标剂量DROI，prescribed，或称为处方剂量，目标剂量DROI，prescribed即被照射体需要实际接收的中子剂量。
在其他实施例中，包括以上参数的部分或者更多未提及参数，都可理解为预设照射参数。
S2：获取预设治疗计划中的预设照射剂量；
在本实施例中，将累积中子计数作为BNCT在线监控系统对于照射剂量的监控参数，通过对累积中子计数的计算和修正，实现对照射剂量的修正，当累积中子计数达到目标值时，照射剂量即达目标剂量。
预设累积中子计数Npreset可采用公式1进行计算，公式1如下：
Npreset＝RBF3，cal×Tpreset      (1)
其中，RBF3,cal为中子剂量检测装置3的理论计数率、Tpreset为预设硼浓度Bpreset对应的预设照射时间，其采用如下公式2进行计算：
预设目标剂量率采用公式3进行计算，公式3如下：
其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应模拟得到的剂量率通过函数拟合得到。
S3：根据预设治疗计划对被照射体S进行照射治疗，并在照射过程中获取实际硼浓度及修正照射剂量；
本发明一实施例中，根据实际硼浓度修正照射剂量得到修正照射剂量，本实施例中获取修正累积中子计数Nupdate作为判断是否达到目标剂量的参数依据。通过血硼浓度检测装置4检测被照射体的血硼浓度，当获得实际血硼浓度Bupdate 后，采用公式4计算实际血硼浓度Bupdate对应的修正累积中子计数Nupdate，公式4如下：
其中，Tupdate为实际血硼浓度Bupdate对应的计划照射时间，为实际血硼浓度Bupdate对应的修正目标剂量率，采用如下公式5进行计算：
其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应模拟得到的剂量率通过函数拟合得到。
S4：根据修正照射剂量实施照射控制。
根据修正照射剂量判断被照射体S接受的照射剂量是否达到目标剂量，当中子剂量检测装置3检测到的累积中子计数到达修正累积中子计数Nupdate时，表明被照射体接受的照射剂量已达到目标剂量DROI，prescribed，控制模块6控制中子束照射模块1停止照射以结束治疗。
可以理解的，如果在治疗过程中，系统一直未获取得到实际硼浓度信息的情况下，则在中子剂量检测装置3检测到的中子剂量到达预设目标剂量时，表明被照射体接受的照射剂量已达到处方剂量DROI，prescribed，控制模块6控制中子束照射模块1停止照射以结束治疗。
本发明一实施例中，在实际照射过程中，中子剂量检测装置3实时检测中子束的照射剂量，当中子照射剂量达到修正照射剂量或预设目标剂量时停止照射；在其他实施方式中，可以通过监测照射时间实现照射控制，具体的，基于修正照射剂量或预设目标剂量计算得到所需要的目标照射时间，当实际照射时间达到目标照射时间时，控制模块6控制中子束照射模块1停止照射以结束治疗，即步骤S4可以是基于目标照射时间实施照射控制。
目标照射时间T采用公式6进行计算，公式6如下：
其中，RBF3,cal是在给定参考射源条件下的BF3比例计数器的计数率，RBF3,QC 是每日束流QC中测量得到的BF3计数率，其反映了照射当日的BF3中子计数率水平，T1为血硼浓度B1对应的照射时间，其采用公式7和8计算得到，公式7和8如下：

在本发明的一实施例中，在执行照射治疗之前采用血硼浓度检测装置4检测被照射体的实际血硼浓度，根据被照射体被执行照射治疗之前的实际血硼浓度计算得到修正的照射时间；在其他实施方式中，在照射过程中，实际照射参数会发生改变，则需要周期性的或实时的根据具体情况对目标照射参数进行调整，以最大限度的确保治疗效果。在对被照射体S进行中子束照射治疗的过程中，需要对被照射体S持续性地供给硼药，而在整个照射过程中，很难保证被照射体体内的硼浓度一直维持在同一个水平。参照公式5所示，目标剂量率随血硼浓度的改变而改变，处方剂量即目标剂量保持不变，当血硼浓度发生改变时，照射剂量和目标照射时间需进行进一步修正以保证被照射体实际接收的中子剂量和处方剂量保持一致，以确保治疗效果。
对应的，本发明的一实施例还可以包括步骤S5，在实际照射过程中实时或周期性的检测被照射体的血硼浓度，根据检测到的血硼浓度实时的或周期性的修正照射剂量或目标照射时间，重复步骤S3-S4，直到中子剂量检测装置3检测到的中子剂量达到目标剂量或实际照射时间等于修正的目标照射时间；另一方面，中子照射模块产生的中子束的参数亦可能发生改变，中子剂量检测装置3能够实时监测中子束的射束参数，当中子束的射束参数发生改变时，亦可适当修正目标照射时间，以保证被照射体实际接收的中子剂量和处方剂量保持一致。
实时检测被照射体的血硼浓度的方法多种多样，本发明的一实施例以通过检测被照射体S释放出的γ射线推算被照射体S体内的硼浓度为例进行描述。中子束进入被照射体体内与硼发生反应后生成γ射线，通过测定γ射线的量可以推算出于中子束发生反应的硼的量，从而推算出被照射体S体内的硼浓度。具体的：硼浓度检测装置检测由中子和硼的反应生成的γ射线(478kev)而测定硼浓度，以能够测定单能量的γ射线而测定硼浓度分布的硼分布测量系统 (PG(Prompt-γ)-SPECT)作为硼浓度检测装置，硼浓度检测装置具有γ射线检测部和硼浓度计算部。γ射线检测部用于检测与从被照射体S的体内放出的γ射线有关的信息，硼浓度计算部根据γ射线检测部检测出的与γ射线有关的信息计算被照射体S体内的硼浓度，γ射线检测部能够使用闪烁器及其他各种γ射线检测设备。在本实施方式中，γ射线检测部配置于被照射体S的肿瘤的附近，例如配置于离被照射体S的肿瘤为30cm左右的位置。
本发明硼中子捕获治疗系统100根据预设血硼浓度模拟得到预设治疗计划，从而获得预设目标剂量，然后根据实际血硼浓度对应的剂量率计算得到修正照射剂量，据此控制中子照射模块实施照射治疗，无需在制定预设治疗计划时向被照射体注射含硼药物，且无需等血硼浓度检测出结果后再实施照射，节约了治疗成本、简化了治疗流程，在治疗过程中根据实际血硼浓度修正目标照射剂量，降低了实际照射时因血硼浓度变化带来的照射剂量的误差。
应该理解的是，虽然如上所述的各实施例所涉及的流程图中的各个步骤按照箭头的指示依次显示，但是这些步骤并不是必然按照箭头指示的顺序依次执行。除非本文中有明确的说明，这些步骤的执行并没有严格的顺序限制，这些步骤可以以其它的顺序执行。而且，如上所述的各实施例所涉及的流程图中的至少一部分步骤可以包括多个步骤或者多个阶段，这些步骤或者阶段并不必然是在同一时刻执行完成，而是可以在不同的时刻执行，这些步骤或者阶段的执行顺序也不必然是依次进行，而是可以与其它步骤或者其它步骤中的步骤或者阶段的至少一部分轮流或者交替地执行。
以上实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对本申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请的保护范围应以所附权利要求为准。

Claims (15)

  1. 一种硼中子捕获治疗系统，其特征在于，包括：
    中子束照射模块，用于产生中子束；
    血硼浓度检测装置，用于检测被照射体的实际血硼浓度；
    治疗计划模块，用于生成预设治疗计划；
    照射剂量修正模块，根据所述实际血硼浓度获得修正照射剂量；及
    控制模块，用于从所述治疗计划模块调取所述预设治疗计划，并根据所述修正照射剂量控制所述中子束照射模块的照射时间，使患者接受的照射剂量达到目标剂量。
  2. 根据权利要求1所述的硼中子捕获治疗系统，其特征在于，所述治疗计划模块根据预设血硼浓度模拟计算得到所述预设治疗计划。
  3. 根据权利要求2所述的硼中子捕获治疗系统，其特征在于，所述照射剂量修正模块根据所述实际血硼浓度修正目标剂量率得到所述修正照射剂量。
  4. 根据权利要求3所述的硼中子捕获治疗系统，其特征在于，还包括用于实时检测累积中子计数而获得照射剂量的中子剂量检测装置。
  5. 根据权利要求4所述的硼中子捕获治疗系统，其特征在于，所述中子剂量检测装置为BF3比例计数器。
  6. 根据权利要求5所述的硼中子捕获治疗系统，其特征在于，预设累积中子计数Npreset采用公式1进行计算，公式1如下：
    Npreset＝RBF3，cal×Tpreset   (1)
    其中，RBF3,cal为中子剂量检测装置的理论计数率、Bpreset为预设硼浓度、Tpreset为预设硼浓度Bpreset对应的预设照射时间，Tpreset采用如下公式2进行计算：
    其中，DROI，prescribed为目标剂量、为预设目标剂量率，采用公式3进行计算，公式3如下：
    其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应的模拟得到的 剂量率通过函数拟合得到。
  7. 根据权利要求4所述的硼中子捕获治疗系统，其特征在于，修正累积中子计数Nupdate采用如下公式4计算：
    其中，Bupdate为实际血硼浓度、Tupdate为实际血硼浓度Bupdate对应的计划照射时间、为实际血硼浓度Bupdate对应的修正目标剂量率，采用如下公式5进行计算：
    其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应的模拟得到的剂量率通过函数拟合得到。
  8. 一种硼中子捕获治疗系统的照射剂量修正方法，其特征在于，包括：
    结合预设硼浓度及被照射体的医学影像数据生成预设治疗计划；
    根据实际硼浓度获得修正照射剂量；及
    根据所述修正照射剂量控制照射时间，使患者接受的照射剂量达到目标剂量。
  9. 根据权利要求8所述的照射剂量修正方法，其特征在于，还包括基于被照射体的医学影像数据确定目标剂量的步骤。
  10. 根据权利要求9所述的照射剂量修正方法，其特征在于，还包括获取预设照射剂量的步骤。
  11. 根据权利要求10所述的照射剂量修正方法，其特征在于，获取所述修正照射剂量具体为：根据实际检测到的硼浓度值修正所述预设治疗计划中的预设目标剂量率得到修正目标剂量率，根据所述修正目标剂量率计算得到所述修正照射剂量。
  12. 根据权利要求10所述的照射剂量修正方法，其特征在于，预设累积中子计数Npreset采用公式1进行计算，公式1如下：
    Npreset＝RBF3，cal×Tpreset  (1)
    其中，RBF3,cal为中子剂量检测装置的理论计数率、Bpreset为预设硼浓度、Tpreset 为预设硼浓度Bpreset对应的预设照射时间，Tpreset采用如下公式2进行计算：
    DROI，prescribed为目标剂量、为预设目标剂量率，采用公式3进行计算，公式3如下：
    其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应模拟得到的剂量率通过函数拟合得到。
  13. 根据权利要求11所述的照射剂量修正方法，其特征在于，所述修正累积中子计数Nupdate采用如下公式4计算：
    其中，Bupdate为实际血硼浓度、Tupdate为实际血硼浓度Bupdate对应的计划照射时间、为实际血硼浓度Bupdate对应的修正目标剂量率，采用如下公式5进行计算：
    其中，a、b、c为拟合系数，其由多个预设硼浓度值和其对应的模拟得到的剂量率通过函数拟合得到。
  14. 一种如权利要求11所述的照射剂量修正方法，其特征在于，还包括用于实时检测照射剂量的中子剂量检测装置，当中子剂量检测装置检测到的照射剂量到达所述修正照射剂量时，控制模块控制中子束照射模块停止照射。
  15. 一种如权利要求14所述的照射剂量修正方法，其特征在于，所述中子剂量检测装置为BF3比例计数器。
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